34-year-old Luis Bonanno of Harleysville was arrested Thursday morning and charged with aggravated assault, endangering the welfare of children and other offenses.
Prosecutors say the investigation began after the baby's mother took the child to an area hospital for breathing problems.
She was transferred to the Children's Hospital of Philadelphia, where doctors found she had suffered a fractured skull, broken ribs and other injuries.
Prosecutors say an investigation by Towamencin Township Police determined Bonanno had caused the injuries by pressing on the baby's chest multiple times.
Bonanno is behind bars in lieu of $100,000 bail.
A preliminary hearing has been set for March 10th.